Propeller drive arrangement

ABSTRACT

A propeller drive arrangement includes a propeller shaft, a planetary gear comprising a first planetary gear member, a second planetary gear member and a third planetary gear member, an outer shaft arranged coaxially with and radially outside of the propeller shaft, A gear wheel set drivingly connecting the second planetary gear member with the outer shaft, The outer shaft is drivingly connected to the one or more propeller blades for varying the pitch angle. 
     The propeller shaft is drivingly fixed to the first planetary gear member, and the second planetary gear member drives the outer shaft via the gear wheel set by a driving torque exerted on the propeller shaft. A pitch controlling actuator controls the pitch angle of the one or more propeller blades,
         to, in a first state, engage the third planetary gear member to a housing so that the propeller shaft and the outer shaft are arranged to rotate with the same rotational speed, and, in a second state, actuate the third planetary gear member so that the third planetary gear member rotates with respect to the housing.

TECHNICAL FIELD

The invention relates to a propeller drive arrangement. The invention also relates to a vessel comprising a propeller drive arrangement.

The invention can be applied in marine vessels, such as in sailing vessels.

BACKGROUND

A marine vessel may comprise a propeller drive arrangement with a propeller hub comprising one or more propeller blades. The pitch angle of the propeller blades may be adjustable.

For example, it is known to equip a sailing vessel with a propeller drive arrangement comprising the above-mentioned propeller hub. The propeller drive arrangement may be driven by a motor, such as by an electric motor, which is powered by use of an electric energy storage system. For example, the energy storage system may be a battery, such as a lithium-ion battery.

During sailing of the sailing vessel, power may be regenerated to the energy storage system, i.e. the electric motor may also function as an electric generator. For this purpose, the pitch angle(s) of the one or more propeller blades may be adjusted to optimize the regeneration of power, e.g. for improved energy efficiency.

Additionally, or alternatively, it may also be advantageous to adjust the pitch angle when a propulsion force is generated by the propeller drive arrangement.

In view of the above, there is a strive to develop a reliable, robust, compact, efficient and/or cost-effective propeller drive arrangement with adjustable propeller blade pitch angle(s).

SUMMARY

An object of the invention is to provide an improved propeller drive arrangement which alleviates at least one drawback of the prior art, or which at least provides a suitable alternative. Another object of the invention is to provide an improved vessel, such as a sailing vessel, which alleviates at least one drawback of the prior art, or which at least provides a suitable alternative.

Thus, there is provided a propeller drive arrangement, comprising:

-   -   a propeller shaft,     -   a propeller hub comprising one or more propeller blades, wherein         a pitch angle of the one or more propeller blades is variable,     -   a planetary gear comprising a first planetary gear member, a         second planetary gear member and a third planetary gear member         which are drivingly connected,     -   an outer shaft arranged coaxially with and radially outside of         the propeller shaft,     -   a gear wheel set drivingly connecting the second planetary gear         member with the outer shaft,     -   wherein the outer shaft is drivingly connected to the one or         more propeller blades for varying the pitch angle,     -   wherein the propeller shaft, in one end thereof, is configured         to be drivingly connected to a propulsion unit and, in a second         end thereof, is drivingly fixed to the propeller hub,     -   wherein the propeller shaft is drivingly fixed to the first         planetary gear member, and     -   wherein the second planetary gear member is arranged to drive         the outer shaft via the gear wheel set by a driving torque         exerted on the propeller shaft, and     -   the propeller drive arrangement further comprising a pitch         controlling actuator for controlling the pitch angle of the one         or more propeller blades,     -   wherein the pitch controlling actuator is arranged to, in a         first state, engage the third planetary gear member to a housing         so that the propeller shaft and the outer shaft are arranged to         rotate with the same rotational speed, and, in a second state,         actuate the third planetary gear member so that the third         planetary gear member rotates with respect to the housing.

By the provision of the propeller drive arrangement as disclosed herein, an improved propeller drive arrangement is achieved. For example, the present invention is based on a realization that the pitch angle can be efficiently controlled by use of a pitch controlling actuator and by only one planetary gear which is drivingly connected to the one or more propeller blades for varying the pitch angle. Thereby, a compact configuration is achieved, implying e.g. a reduced need of adding further gears for achieving the function of the propeller drive arrangement. This also implies a more reliable and robust configuration since few components are required for the pitch angle function of the propeller drive arrangement.

By controlling the pitch angle by the pitch controlling actuator as disclosed herein is meant to vary, or adjust, the pitch angle of the one or more propeller blades, and also to maintain the one or more propeller blades at a fixed pitch angle. The pitch angle of each propeller blade is adjusted with respect to a respective pitch angle rotational axis of the respective propeller blade. The pitch angle rotational axis of each propeller blade preferably extends along a radial direction of the propeller shaft.

When the propeller shaft and the outer shaft rotate with the same rotational speed, the pitch angle of the one or more propeller blades is fixed. In addition, when the third planetary gear member rotates with respect to the housing, the pitch angle of the one or more propeller blades is adjusted.

Each one of the first, second and third planetary gear members of the planetary gear is a respective one of a sun gear, a planet carrier carrying a plurality of planetary gear wheels, and a ring gear. Accordingly, by way of example, several different combinations are feasible for achieving the variable pitch angle function as disclosed herein. For example, if the pitch controlling actuator is used for engaging the ring gear to the housing, the propeller shaft may either be drivingly fixed to the sun gear or to the planet carrier. In other words, it has been realized that six different configurations are feasible, or three times two different configurations.

Optionally, the first planetary gear member is a sun gear of the planetary gear. This implies a simplified configuration where the sun gear, which is closest to a rotational axis of the planetary gear, is drivingly fixed to the propeller shaft.

Still optionally, the second planetary gear member is a planet carrier of the planetary gear carrying a plurality of planetary gear wheels. The planetary gear wheels are rotationally arranged on the planet carrier and drivingly connect the sun gear and the ring gear. This also implies a simplified configuration where the planet carrier is drivingly connected to the outer shaft via the gear wheel set. For example, the planet carrier may comprise gear teeth which are in meshing engagement with gear teeth of the gear wheel set. Still optionally, the planet carrier comprising the gear teeth for the gear wheel set may be made in one single piece, implying a robust and compact configuration.

Still optionally, the third planetary gear member is a ring gear of the planetary gear. This implies a facilitated connection interface between the planetary gear and the pitch controlling actuator since the ring gear is the outermost member of the planetary gear. For example, the ring gear may comprise gear teeth on a radially outer peripheral surface of the ring gear for the pitch controlling actuator. Additionally, or alternatively, the ring gear may comprise gear teeth on an axial side face of the ring gear for the pitch controlling actuator, such as an axial side face which faces away from the one or more propeller blades. Still optionally, the ring gear with the gear teeth for the pitch controlling actuator may be made in one single piece, implying a robust and compact configuration.

Optionally, the pitch controlling actuator is a rotary actuator, such as an electromechanical rotary actuator, which is configured to rotate the third planetary gear member with respect to the housing. Even though the pitch controlling actuator preferably is an electromechanical actuator, it shall be noted that also other actuators may be used, such as pneumatic and hydraulic actuators.

Optionally, the outer shaft is arranged to rotate one full revolution or more than one full revolution with respect to the propeller shaft. Thereby, the pitch angle of the one or more propeller blades may be set to any angle, i.e., an angle of 0 to 360 degrees with respect to a pitch angle rotational axis of the respective propeller blade.

Optionally, the pitch controlling actuator is arranged to, in the second state, actuate the third planetary gear member in any rotational direction with respect to the housing. Thereby, the pitch angle can be adjusted in any direction, implying faster and more efficient pitch angle adjustment.

Optionally, the gear wheel set has a fixed gear ratio which allows the propeller shaft and the outer shaft to rotate with the same rotational speed when the pitch controlling actuator is provided in the first state. A fixed gear ratio implies a simplified and compact configuration.

Optionally, the gear wheel set comprises a first gear wheel which is in meshing engagement with an auxiliary gear wheel of the second planetary gear member, and the gear wheel set further comprises a second gear wheel, which is rotationally fixed to the first gear wheel and which is in meshing engagement with an outer shaft gear wheel which is rotationally fixed to the outer shaft. This implies a robust and compact gear wheel set. The first and second the gear wheels may be made in one single piece. The auxiliary gear wheel may be integrated with the second planetary gear member, i.e. made in one single piece.

Optionally, the propeller drive arrangement further comprises a bevel gear arrangement drivingly connecting the outer shaft to the one or more propeller blades.

Optionally, the propeller drive arrangement comprises only one planetary gear. This implies a compact configuration.

According to a second aspect of the invention, there is provided a vessel, such as a sailing vessel, comprising a propeller drive arrangement according to any one of the embodiments of the first aspect of the invention.

Advantages and effects of the second aspect of the invention are analogous to the advantages and effects of the first aspect of the invention.

Further advantages and advantageous features of the invention are disclosed in the following description and in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

In the drawings:

FIG. 1 is a sectional view of a propeller drive arrangement according to an example embodiment of the present invention, and

FIG. 2 is a side view of a vessel according to an example embodiment of the present invention.

The drawings are schematic and not necessarily drawn to scale. It shall be understood that the embodiments shown and described are exemplifying and that the disclosure is not limited to these embodiments. It shall also be noted that some details in the drawings may be exaggerated in order to better describe and illustrate the disclosure. Like reference characters throughout the drawings refer to the same, or similar, type of element unless expressed otherwise.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

FIG. 1 depicts a sectional view of a propeller drive arrangement 1 according to an example embodiment of the present invention. The propeller drive arrangement 1 comprises a propeller shaft 10. The sectional view is including a rotational axis A of the propeller shaft 10.

The propeller drive arrangement 1 comprises:

-   -   the propeller shaft 10, and     -   a propeller hub 20 comprising one or more propeller blades 22,         24, wherein a pitch angle of the one or more propeller blades         22, 24 is variable.

The propeller drive arrangement 1 further comprises a planetary gear 30. The planetary gear 30 comprises a first planetary gear member 32, a second planetary gear member 34 and a third planetary gear member 36 which are drivingly connected. The planetary gear 30 is coaxially arranged on the propeller shaft 10.

In the shown embodiment, the first planetary gear member 32 is a sun gear, the second planetary gear member 34 is a planet carrier 34 carrying a plurality of planetary gear wheels 342, and the third planetary gear member 36 is a ring gear. The planetary gear wheels 342 are rotationally arranged on the planet carrier 34 and drivingly connecting the sun gear 32 and the ring gear 36.

The propeller drive arrangement 1 further comprises an outer shaft 40 arranged coaxially with and radially outside of the propeller shaft 10.

It further comprises a gear wheel set 42 drivingly connecting the second planetary gear member 34 with the outer shaft 40.

The outer shaft 40 is drivingly connected to the one or more propeller blades 22, 24 for varying the pitch angle, and the propeller shaft 10, in one end 12 thereof, is configured to be drivingly connected to a propulsion unit (not shown) and, in a second end 14 thereof, is drivingly fixed to the propeller hub 20.

Moreover, the propeller shaft 10 is drivingly fixed to the first planetary gear member 32, and the second planetary gear member 34 is arranged to drive the outer shaft 40 via the gear wheel set 42 by a driving torque exerted on the propeller shaft 10, and the propeller drive arrangement 1 further comprises a pitch controlling actuator 50 for controlling the pitch angle of the one or more propeller blades 22, 24.

The pitch controlling actuator 50 is arranged to, in a first state, engage the third planetary gear member 36 to a housing (not shown) so that the propeller shaft 10 and the outer shaft 40 are arranged to rotate with the same rotational speed, and, in a second state, actuate the third planetary gear member 36 so that the third planetary gear member 36 rotates with respect to the housing.

More specifically, the propeller drive arrangement 1 is configured so that, when the propeller shaft 10 and the outer shaft 40 rotate with the same rotational speed, the pitch angle of the one or more propeller blades 22, 24 is fixed. In addition, it is further configured so that, when the third planetary gear member 36 rotates with respect to the housing, the pitch angle of the one or more propeller blades 22, 24 is adjusted.

The pitch angle of each propeller blade 22, 24 is adjusted with respect to a respective pitch angle rotational axis A2, A3 of the respective propeller blade 22, 24. The pitch angle rotational axis A2, A3 of each propeller blade 22, 24 extends along a radial direction of the propeller shaft 10.

Even though the shown configuration may be a preferred configuration, it shall be noted that other configurations are feasible. More specifically, by using a planetary gear 30, it has been realized that six different combinations are possible, depending on which member of the planetary gear 30 the outer shaft 40 is in driving connection with, and also depending on which other member of the planetary gear 30 the pitch controlling actuator is configured to actuate.

As shown in FIG. 1 , the pitch controlling actuator 50 may be a rotary actuator, herein an electromechanical rotary actuator, which is configured to rotate the third planetary gear member 36 with respect to the housing. More specifically, in the shown embodiment, the rotary actuator 50 comprises a shaft 52 arranged to rotate with respect to a rotational axis A1 of the rotary actuator 50. The rotational axis A1 of the rotary actuator 50 is in the shown embodiment provided in parallel with the rotational axis A of the propeller shaft 10.

This implies a compact configuration. It shall however be noted that other configurations are feasible, such as providing a rotary actuator having a shaft with a rotational axis which is perpendicular to the rotational axis A of the propeller shaft 10, such as a rotational axis of the rotary actuator which is aligned with a radial direction of the propeller shaft 10.

The rotary actuator 50 comprises an actuator gear wheel 54 provided on the shaft 52. Gear teeth of the actuator gear wheel 54 are in meshing engagement with gear teeth 362 of the ring gear 36. The gear teeth 362 are in the shown embodiment provided on a radially outer peripheral surface of the ring gear 36.

Furthermore, in the shown embodiment, the outer shaft 40 is arranged to rotate one full revolution or more than one full revolution with respect to the propeller shaft 10. In other words, in the shown embodiment, the outer shaft 40 is freely rotatable with respect to the propeller shaft 10. The outer shaft 40 may be supported by bearings (not shown) provided in-between the propeller shaft 10 and the outer shaft 40. The bearings may be ball bearings or roller bearings.

The pitch controlling actuator 50 may be arranged to, in the second state, actuate the third planetary gear member 36 in any rotational direction with respect to the housing. Accordingly, the pitch controlling actuator 50 may be arranged to, in the second state, actuate the third planetary gear member 36 in any rotational direction with respect to the rotational axis A, i.e. in a clockwise and an anti-clockwise direction. This is achieved by rotating the shaft 52 in the clockwise or the anti-clockwise direction about the rotational axis A1. Thereby, the pitch angle of the propeller blades 22, 24 can be adjusted in any direction. Accordingly, the pitch angle can thereby for example be quickly adjusted back and forth between two different angular positions. The pitch controlling actuator 50 may be controlled by a control unit (not shown) which issues control signals to the pitch controlling actuator 50.

The gear wheel set 42 as shown in FIG. 1 has a fixed gear ratio which allows the propeller shaft 10 and the outer shaft 40 to rotate with the same rotational speed when the pitch controlling actuator 50 is provided in the first state. More specifically, as shown, the gear wheel set 42 may comprise a first gear wheel 421 which is in meshing engagement with an auxiliary gear wheel 341 of the second planetary gear member 34, and the gear wheel set 42 may further comprise a second gear wheel 422, which is rotationally fixed to the first gear wheel 421 and which is in meshing engagement with an outer shaft gear wheel 401, which is rotationally fixed to the outer shaft 40. In the shown embodiment, the first gear wheel 421 and the second gear wheel 422 are made in one single piece. In the shown embodiment, each one of the first gearwheel 421, the second gearwheel 422 and the outer shaft gearwheel 401 comprises respective gear teeth provided on a respective radially outer peripheral surface.

The propeller drive arrangement 1 as shown in FIG. 1 further comprises a bevel gear arrangement 44 drivingly connecting the outer shaft 40 to the one or more propeller blades 22, 24. Accordingly, a rotational motion about the axis A of the outer shaft 40 relative to the propeller shaft 10 can be translated to rotational motions of the propeller blades 22, 24 with respect to the pitch angle rotational axes A2, A3.

As further depicted in FIG. 1 , the propeller drive arrangement 1 preferably comprises only one planetary gear 30, thereby enabling a compact, low-weight and cost-effective configuration.

FIG. 2 depicts a side view of a vessel 100 according to an example embodiment of the invention. The vessel 100 is a marine vessel, and more particularly a sailing vessel comprising at least one sailing rig 110. The vessel 100 further comprises a propeller drive arrangement 1 according to an embodiment of the invention, such as the propeller drive arrangement 1 shown in FIG. 1 . The propeller drive arrangement 1 may be used for generating a propulsion force by a propulsion unit 120, such as an electric motor. The propeller drive arrangement 1 may also be used for regenerating power to an energy storage system (not shown), e.g. a battery, when the vessel 100 is using the sailing rig 110 for generating the propulsion force. By varying the pitch angle during use of the vessel 100, the regenerative power generation and/or the propulsion force can for example be optimized for improved energy efficiency.

It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims. 

1. A propeller drive arrangement, comprising: a propeller shaft, a propeller hub comprising one or more propeller blades, wherein a pitch angle of the one or more propeller blades is variable, a planetary gear comprising a first planetary gear member, a second planetary gear member and a third planetary gear member which are drivingly connected, an outer shaft arranged coaxially with and radially outside of the propeller shaft, a gear wheel set drivingly connecting the second planetary gear member with the outer shaft, wherein the outer shaft is drivingly connected to the one or more propeller blades for varying the pitch angle, wherein the propeller shaft, in one end thereof, is configured to be drivingly connected to a propulsion unit and, in a second end thereof, is drivingly fixed to the propeller hub, wherein the propeller shaft is drivingly fixed to the first planetary gear member, and wherein the second planetary gear member is arranged to drive the outer shaft via the gear wheel set by a driving torque exerted on the propeller shaft, and the propeller drive arrangement further comprising a pitch controlling actuator for controlling the pitch angle of the one or more propeller blades, wherein the pitch controlling actuator is arranged to, in a first state, engage the third planetary gear member to a housing so that the propeller shaft and the outer shaft are arranged to rotate with the same rotational speed, and, in a second state, actuate the third planetary gear member so that the third planetary gear member rotates with respect to the housing.
 2. The propeller drive arrangement according to claim 1, wherein the first planetary gear member is a sun gear of the planetary gear.
 3. The propeller drive arrangement according to claim 1, wherein the second planetary gear member is a planet carrier of the planetary gear carrying a plurality of planetary gear wheels.
 4. The propeller drive arrangement according to claim 1, wherein the third planetary gear member is a ring gear of the planetary gear.
 5. The propeller drive arrangement according to claim 1, wherein the pitch controlling actuator is a rotary actuator, such as an electromechanical rotary actuator, which is configured to rotate the third planetary gear member with respect to the housing.
 6. The propeller drive arrangement according to claim 1, wherein the outer shaft is arranged to rotate one full revolution or more than one full revolution with respect to the propeller shaft.
 7. The propeller drive arrangement according to claim 1, wherein the pitch controlling actuator is arranged to, in the second state, actuate the third planetary gear member in any rotational direction with respect to the housing.
 8. The propeller drive arrangement according to claim 1, wherein the gear wheel set has a fixed gear ratio which allows the propeller shaft and the outer shaft to rotate with the same rotational speed when the pitch controlling actuator is provided in the first state.
 9. The propeller drive arrangement according to claim 8, wherein the gear wheel set comprises a first gear wheel which is in meshing engagement with an auxiliary gear wheel of the second planetary gear member, and wherein the gear wheel set further comprises a second gear wheel, which is rotationally fixed to the first gear wheel and which is in meshing engagement with an outer shaft gear wheel which is rotationally fixed to the outer shaft.
 10. The propeller drive arrangement according to claim 9, wherein the first gear wheel and the second gear wheel are made in one single piece.
 11. The propeller drive arrangement according to claim 1, further comprising a bevel gear arrangement drivingly connecting the outer shaft to the one or more propeller blades.
 12. The propeller drive arrangement according to claim 1, wherein the propeller drive arrangement comprises only one planetary gear.
 13. A vessel, such as a sailing vessel, comprising a propeller drive arrangement according to claim
 1. 